1. Field of the Invention
The present invention relates to a system for biometric input, comparison, and authentication and, more particularly, to a system and method for securing one or more files, including data files and applications, by restricting available access thereto to authorized individuals through the use of a biometric input device. The biometric input device provides a compact, yet highly functional configuration and an associated biometric data comparison system provides for controlled access to a computing system based upon comparison of inputed biometric data with biometric data stored in a database.
2. Description of the Related Art
Biometric input devices are known for use with computing systems. Such biometric input devices include computer mouse designs. Existing designs for such biometric input devices have scanning windows lacking efficient positioning structure for scanning positioning and protection from ambient light, and do not provide mechanical integration of a position sensing ball assembly with an optical scanning assembly maximizing reliability of position sensing ball operation.
Biometric data comparison methods and systems are known. Such known systems and methods suffer from various drawbacks including intensive computing power requirements, intensive memory requirements, slow data transfer, slow comparison, and comparison reliability reduction due to environmental and physiological factors. Known systems also fail to provide for secure communication of biometric data over public lines.
Additionally, traditional, commercially available file securing systems are often minimally secure, and if enhanced to the point of providing effective security, are rather difficult and/or complex to utilize, requiring a series of complex steps be performed, and/or requiring the secure maintenance of a password. Naturally, password security systems are not optimally secure unless very elaborate and/or require very long passwords. Accordingly, there is a need for a system which can be convenient and easy to use, but which also provides a substantial amount of security to the files to be secured.
Accordingly, it is an object of the invention to provide a system and method for biometric input and comparison which overcomes the drawbacks of the prior art.
It is a further object of the invention to provide an ergonomically advantageous biometric input device which ensures increased precision in sampling biometric data.
It is a still further object of the invention to provide a biometric data comparison method which controls access to computers or data networks.
It is yet another object of the invention to provide a fingerprint comparison method which provides for accurate and rapid comparison of fingerprints while compensating for environmental and physiological factors.
An object of the present invention is also to provide a biometric based access control system for use on computers which permits a user to graphically apply biometric access control features to data and applications by the use of a user manipulated biometric protection icon.
Briefly stated, the present invention provides a biometric input device, system and method which includes a biometric input device having a scanning window surrounded by a ridge for ensuring positive positioning of a biometric sample such as a thumb. The biometric input device includes an optical assembly having a prism with a focusing lens disposed on a side thereof and optionally integrally formed therewith. A biometric comparison method is provided for comparing data from said biometric input device with data from a database using both directional image comparison and clusterized minutia location and direction comparison. A further system is provided for allowing access to computer functions base on the outcome of the comparison method.
The present invention also provides a biometric input device for accepting a fingerprint of a finger tip having opposing tip sides and a tip end, comprising a device body having a body wall defining an aperture and an optical assembly for scanning the fingerprint disposed in the device body. The optical assembly has a scanning surface at the aperture upon which the finger tip is placed for scanning of the fingerprint by the optical assembly. A ridge surrounds a portion of a periphery of the aperture such that the ridge engages the opposing tip sides and tip end such as to position the fingerprint on the scanning surface and block ambient light.
A further feature of the present invention includes the aforesaid biometric input device having a device body with a bottom surface opposing a substrate upon which the device body is placed, a device body length and a front portion, a middle portion and a heel portion. A movement detection device for detecting movement of the device body relative the substrate is provided and the bottom surface defines a bottom surface aperture through which the movement detection device detects movement of the device body relative to the substrate. The bottom surface aperture is disposed in the heel portion of the device body and the optical assembly is disposed in the middle portion of the device body. In an embodiment of the present invention the movement detection device has a ball protruding through the bottom surface aperture for engaging the substrate to register the movement of the device body relative the substrate.
According to a feature of the invention, there is further provided a biometric input device for accepting a fingerprint of a finger tip having opposing tip sides and a tip end, comprising a device body having a body side wall defining an aperture, and an optical assembly for scanning the fingerprint disposed in the device body. The optical assembly includes an imaging component for converting a light image into pixel output and a lens for focusing the light image into the imaging component. The optical assembly includes a prism with first, second and third sides and a top side wherein the first side forms a scanning surface at the aperture upon which the finger tip is placed for scanning of the fingerprint by the optical assembly, the second side has the lens for focusing the light image into the imaging component disposed thereon, and the third side has a light absorbing layer.
The present invention also includes the above embodiment wherein, in the alternative or in combination with one another, the lens is formed integrally with the prism and a light emitting device is disposed to emit light into the prism from the top side of the prism to illuminate the fingerprint when disposed at the scanning surface.
According to a still further feature of the invention, there is provided a biometric comparison method comprising a series of steps beginning with (a) scanning in a fingerprint and digitizing the scanning signals to produce a matrix of print image data representing pixels. Next the method proceeds with (b) dividing the print image data into cells, each including a number of pixel data for contiguous pixels, and (c) calculating a matrix of directional image data DI using gradient statistics applied to the cells wherein the directional image data DI includes, for each of the cells, a cell position indicator and one of a cell vector indicative of a direction of ridge lines and an unidirectional flag indicative of a nondirectional calculation result. Processing then continues with (d) skeletonizing the print image data, and (e) extracting minutia from the print image data and producing a minutia data set comprised of data triplets for each minutia extracted, including minutia position data and minutia direction data.
Next, a comparing process is initiated by (f) providing reference fingerprint data from a database wherein the reference fingerprint data includes reference directional image data DI and a reference minutia data set, and (g) performing successive comparisons of the directional image data DI with the reference directional image data DI and determining a directional difference DifDI for each of the successive comparisons wherein for each of the successive comparisons one of the directional image data DI and the reference directional image data DI is positional shifted by adding position shift data. In a next step (h) it is determined for which of the successive comparisons the directional difference DifDI is the least and the position shift data thereof is selected as initial minutia shift data. A next stage of the comparison process proceeds with (i) positional shifting minutia data by applying the initial minutia shift data to one of the minutia data sets and the reference minutia data set to initially positionally shift the minutia position data and the minutia orientation data, then (j) performing successive comparisons of the minutia data set with the reference minutia data set following the positional shifting minutia data and determining matching minutia based on a minutia distance criteria, a number of matching minutia, and a similarity measure indicative of correspondence of the matching minutia for each of the successive comparisons wherein, for each of the successive comparisons, one of the minutia data set and the reference minutia data set is positional shifted within a minutia shift range R by adding minutia position shift data, and finally (k) determining a maximum similarity measure of the similarity measures of the successive comparisons. The comparison method concludes with (l) determining whether the maximum similarity measure is above a similarity threshold and indicating the reference fingerprint data and the fingerprint data are from the same fingerprint when the maximum similarity measure is above the similarity threshold.
The present invention also includes the above method wherein, as an alternative, the calculation of the directional image data includes (c1) identifying a directional group of cells comprising all cells of the cells that do not have the unidirectional flag associated therewith; and then excluding from the successive comparisons of minutia data sets, one of the minutia data sets and the reference minutia data set located in or positionally aligned with the cells that have the unidirectional flag associated therewith.
The present invention further provides a feature for use in conducting the successive comparisons of minutia comprising dividing the minutia data set into the minutia data set clusters formed on contiguous ones the cells and each including a predetermined number of the minutia before conducting the successive comparisons, conducting the successive comparisons for each of the minutia data set clusters and determining for each of the minutia data set clusters a maximum similarity measure, and finally determining the maximum similarity measure as a sum of the maximum similarity measures of each of the minutia data set clusters.
The present invention also provides for the above comparison method excluding from further processing pairs of the minutia located within a minutia exclusion distance of one another and having minutia direction data with a direction exclusion limit of being in opposite directions.
The present invention further provides a feature wherein in the above comparison method the minutia extraction step extracts minutia limited to ends and bifurcations. Still further there is provided a feature wherein the minutia data set excludes data distinguishing ends and bifurcations.
Yet another feature of the present invention is a biometric comparison system comprising a computer processor assembly preferably having a memory including a reference fingerprint data and at least one of file data and application software, a display, an apparatus for representing at least one of the file data and application software as icons on the display, and a biometric input device, preferably as part of a biometric access control assembly for scanning a fingerprint and storing fingerprint data representing the fingerprint into the memory. A comparison engine is provided for comparing the fingerprint data with the reference fingerprint data and determining a match if a similarity threshold is satisfied. An access control icon generator permits a user to move an access control icon on the display and an access control means is provided for controlling access to the at least one of file, be it a data file and/or an application, when a user moves the access control icon onto the icon representing the file, and/or visa versa, whereby access to the at least one file is permitted only if a user scans a fingerprint producing fingerprint data for which the comparison means determines matches the reference fingerprint data and designates the user as authorized user.
The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements.